Matthieu Pizenberg (Dec 01 2025 at 17:47): Matthieu Pizenberg (Dec 01 2025 at 17:47):I opened an issue here: https://github.com/roc-lang/roc/issues/8532
Richard Feldman (Dec 01 2025 at 18:08):thanks! I'll look into these today
Matthieu Pizenberg (Dec 01 2025 at 18:09):I might find the issue soon. Looking into it now.
Matthieu Pizenberg (Dec 01 2025 at 18:22):The segfault is due to dropPrefix using substringUnsafe without incrementing the ref count it seems. Well the function only increment when the prefix doesn’t match. I’m not sure why.
https://github.com/roc-lang/roc/blob/968e8776e2f69438135b3155829a2d9a556dd201/src/builtins/str.zig#L809
Luke Boswell (Dec 01 2025 at 20:32):Do we have a fix for this yet? I think I can fix it also
Matthieu Pizenberg (Dec 01 2025 at 20:33):Yeah @Richard Feldman has a fix in a branch that isn’t in a PR yet.
Matthieu Pizenberg (Dec 01 2025 at 20:34):https://github.com/roc-lang/roc/compare/main...fix-uaf
Matthieu Pizenberg (Dec 01 2025 at 20:36):I think once it’s merged, and my modulus pr is accepted too (https://github.com/roc-lang/roc/pull/8528), AoC day 1 is easily doable (I have some code ready to share ^^)
Luke Boswell (Dec 01 2025 at 20:38):I'll look at your pr now
Luke Boswell (Dec 01 2025 at 20:56):I am looking at another PR and have to push some commits to fix it, I can add the fix for drop_prefix in there too
Luke Boswell (Dec 01 2025 at 21:02):Cherry picked and added into https://github.com/roc-lang/roc/pull/8520
Richard Feldman (Dec 01 2025 at 21:23):fix for the use-after-free: https://github.com/roc-lang/roc/pull/8535
Luke Boswell (Dec 01 2025 at 21:28):I resolved some merge conflicts between these branches so no harm that commit being in both PRs
Last updated: Dec 21 2025 at 12:15 UTC